INTERNATIONAL EARTH ROTATION SERVICE (IERS)
SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE
BUREAU CENTRAL DE L'IERS
OBSERVATOIRE DE PARIS Paris, 6 January 1997
61, Av. de l'Observatoire 75014 PARIS (France)
Tel. : 33 (0) 1 40 51 22 26
FAX : 33 (0) 1 40 51 22 91
Internet : iers@obspm.fr
Bulletin C 13
To authorities responsible for
the measurement and distribution
of time
UTC TIME STEP
on the 1st of July 1997
A positive leap second will be introduced at the end of June 1997.
The sequence of dates of the UTC second markers will be:
1997 June 30, 23h 59mn 59s
1997 June 30, 23h 59mn 60s
1997 July 1, 0h 0mn 0s
The difference between UTC and the International Atomic Time TAI is:
from 1996 January 1, 0h UTC, until 1997 July 1, 0h UTC: UTC-TAI = - 30s
from 1997 July 1, 0h UTC, until further notice : UTC-TAI = - 31s
Leap seconds can be introduced in UTC at the end of the months of December
or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every
six months, either to announce a time step in UTC, or to confirm that
there will be no time step at the next possible date.
Martine FEISSEL
Director
Central Bureau of IERS